For example, a conversion device (power conditioner) for interconnecting output of a solar battery module with a commercial power grid includes a DC/DC converter and an inverter. The output of the solar battery module is stepped up by the DC/DC converter, and thus a predetermined voltage is supplied to a DC bus to which a smoothing capacitor is connected. On the basis of the voltage of the DC bus, an AC voltage and an AC current are outputted by the inverter (see, for example, Patent Literature 1).
In addition, as a conversion device including a DC/DC converter and an inverter, the following technique is proposed: the DC/DC converter at the preceding stage generates a voltage having a pulsating current waveform, and the inverter at the subsequent stage inverts the polarity of the generated voltage per one pulsating current cycle, thereby generating an AC voltage waveform (see, for example, Patent Literature 2).
In addition, in a power interconnection inverter device composed of a DC/DC converter including a DC reactor and a polarity-switching inverter including an AC reactor, the following technique is proposed: in order to reduce current distortion on the AC side, an intermediate-stage capacitor current is compensated in a feed-forward manner in calculation of a current command value for the DC reactor (see, for example, Patent Literature 3).